The long term objective of this project is the development of truly novel sulfur-based methodology which can be used for the synthesis of compounds which are either medicinally important or which can be used for the determination of the relationship between structure and biological activity. Most of the major new methods to be studied involve as a key step either the displacement of thiophenoxide ions from carbanionic sites in the same molecule to produce usefully functionalized cyclopropanes, which can be used in a variety of synthetic procedures, or the treatment of compounds containing phenylthio groups with lithium 1-(dimethylamino)naphthalenide in order to generate radicals or anions, which have multiple synthetic uses. These two types of fundamental processes, when combined with a number of other novel synthetic concepts should lead to a variety of new methods for the synthesis and modification of rings from 3 to 10 members. Among the new techniques suggested are methods for the efficient construction of a large variety of cyclopropanes, including vinyl- and divinylcyclopropanes, and allylidenecyclopropanes and of 2-vinyl-cyclobutanones and 2,3-divinylcyclobutanones as well as methods of expansion of all of these types to usefully functionalized larger rings. New methods are also proposed for the vinylation of carbanions, the olefination of ketones, the regiospecific formation of various anions, including dianions and Alpha-lithioepoxides, substitution of the anomeric carbon atom of sugars by carbon electrophiles, the production of sulfur-substituted diazo compounds and carbenoids, the ring contraction of lactones to carbocycles, and the preparation of spiroketals and hydrazulenes.